// 在区间[0, end)生成num个无序的数组
function generateArr(num, end) {
  const arr = [];
  for (let i = 0; i < num; i++) {
    // eslint-disable-next-line no-unused-expressions
    arr[i] = Math.floor(Math.random() * end);
  }
  return arr;
}

console.log(generateArr(19, 20));
